Yellowing new growth on most plants within just a few days in VEG

Thinking its either an Iron, Potassium or Magnesium. They are 1 month from seed and got moved from T5s to 4 600w LEDs in a co2 controlled room @ 1500ppm, so Im thinking I put these plants in there too early with the co2 too high and caused them to grow too fast at such a young age.

So now I slowed things down and they are vegging under 1 600w MH and now Im just trying to get them healthy again. So any input would be nice. I have been doing a foilar spray of Spray n Grow Iron and Zinc, also did foilar spray of some Epsom salts for the Mag.

Im leaning toward a Potassium def. So gonna get some Earth Juice Meta K tomorrow.

What you are seeing is basic light burn from the switch from low light to heavy LED lighting, that for sure can cause burning. I would feed something high in (K) to help relieve the stress and move your lights about a foot further from your canopy.

I had the lights hung about 4 ft above canopy.

Fix the ph ,the yellowing is the ph wrong.

PH is fine, using the same water for outdoor plants and they are doing great...
PH is always tested before watering always 6.2-6.8

Just gave them some Earth Juice MicroBlast, I can tell that they are doing alot better than last week.

So just checked upon them 2 days after micro blast feeding and they look to be getting better. Im thinking it was too much co2 at too early of an age made them grow too fast...